Merge branch 'fix/transient-failing-analytics-spec' into 'master'

Fix transient failure on AnalyticsBuildEntity

AnalyticsBuildEntity uses `Time.now` to calculate durations, and on slow running builds could fail this spec. Mocking with `Timecop` should be sufficient to fix this.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/25500

See merge request !8082

spec/serializers/analytics_build_entity_spec.rb

@@ -13,6 +13,14 @@ describe AnalyticsBuildEntity do
 
     subject { entity.as_json }
 
+    before do
+      Timecop.freeze
+    end
+
+    after do
+      Timecop.return
+    end
+
     it 'contains the URL' do
       expect(subject).to include(:url)
     end